|
9.1 Physical properties of elements
of Period 2 and Period 3
|
10 5
|
Candidates should be able to:
(a) interpret and explain the
trend and gradation of atomic radius,
melting point, boiling point, enthalpy change of vaporisation and electrical
conductivity in terms of structure and bonding;
(b) explain the factors
influencing ionization energies;
(c) explain the trend in ionization
energies across Period 2 and Period 3 and down a group
(d) Predict the electronic
configuration and position of unknown elements in the Periodic Table from
successive values of ionization energies.
|
|
|
||
|
9.2 Reactions of Period 3 elements
with oxygen and water
|
2
|
Candidates should be able to:
(a) describe the reactions of
Period 3 elements with oxygen and water;
(b) interpret the ability of
elements to act as oxidizing and reducing agents.
|
|
9.3 Acidic and basic properties of
oxides and hydrolysis of oxides
|
3
|
Candidates should be able to:
(a) explain the acidic and
basic properties of the oxides of Period 3 elements;
(b) describe the reactions of
the oxides of Period 3 elements with water;
(c) describe the
classification of the oxides of Period 3 elements as basic, amphoteric or
acidic based on their reactions with water, acid and alkali;
(d) describe the use of
sulphur dioxide in food preservation.
|
1.
Melting point of the elements are depend on the type of bonding formed between the element and the structure formed.
2.
Basically, the stronger the bond the higher the melting point and boiling point
because more energy are required to overcome the forces of attraction (FOA)
between the particles.
3.
Element may exist as metal , semi-metal and non-metal.
4.
Thus, the bond that may exist in the element are ;
a) metallic bonding
b) Giant molecular structure (covalent)
c) simple molecule (covalent)
EXAM QUESTION STPM 2011
1a) Chlorine, oxygen and sulphur are three
elements on the right hand side of the periodical table. These element can form
Cl- , O2- and S2- ion respectively.
(i)
what is meant by isoelectronic? [1
marks]
(ii)
Arrange the ions in order of increasing size. Explain your answer
[3 marks]
b) The
variation in the melting point and boiling point of eight element in the
periodical table are shown in the data below
Based
on the data below, explain the following explanation:
Period 3
|
||||||||
Element
|
Na
|
Mg
|
Al
|
Si
|
P
|
S
|
Cl
|
Ar
|
m.p./K
|
371
|
922
|
933
|
1683
|
317
|
392
|
172
|
84
|
b.p./K
|
1156
|
1380
|
2740
|
2328
|
553
|
718
|
238
|
87
|
(i)
The boiling point increase from Na to Al [3
marks]
(ii)
Si has the highest melting point [2
marks]
(iii)
The value of te melting point and boiling point of Ar are almost the same [1
marks]
STPM 2012
2a)
Explain the trend in acid-base properties of the oxides of Period 3 element of
the Periodical table [2marks]
2b)
Aluminium is an amphoteric compound.
i)
what is meant by amphoteric compound ?
[1 marks]
ii)
write balanced equations to show the amphoteric behaviour of aluminium oxide [2
marks]
1. The successive ionization energies, in kJ mol-1 , of an element in the Periodic Table are given below.
940 (First), 2080, 3090, 4140, 7030, 7870, 16 000, 19 500
In which group in the Periodic Table is this element likely to be located? [STPM 2000]
A Group 13 B Group 14 C Group 15 D Group 16 E Group 17
2. Which of the following properties best characterizes metals with metallic bonds? [STPM 2000]
A High density
B High melting point
C Low electronegativity
D High solubility in water
E Electric conductor in the solid state
3. Which of the following statements is true regarding the oxides of the elements in
Period 3 (sodium to chlorine) of the Periodic Table? [STPM 2000]
A Sodium oxide is the strongest base because sodium is the most electropositive element in Period 3.
B Going across Period 3 the properties of the oxides changes from base to acid because the bond
between the element and Oxygen gets stronger.
between the element and Oxygen gets stronger.
C Aluminium oxide is amphoteric because it is in Group 13.
D Oxide of phosphorous forms the strongest acid because it is the most soluble in water.
E Silicon dioxide does not react with aqueous sodium hydroxide because it is neutral.
4. Mendeleev arranged the elements in the Periodic Table based on the order of …… [STPM 2001]
A increasing proton number
B increasing relative atomic mass
C increasing molar volume
D increasing atomic size
No comments:
Post a Comment